1. Field of the Invention
The invention relates to a tipping-conveyor element for a package conveyor, whose driven conveyor line consists of a multiplicity of conveyor elements flexibly connected to one another, elements on whose carrying surface, being essentially horizontal in the conveying state, there is to be placed in each case at least one package which, by tipping the carrying surface, is to be delivered, laterally to the conveying direction, selectively to one of several delivery stations provided along the conveying section, with a carrying element exhibiting the carrying surface, an element that is braced by a support device on a support part that is movable along a guideway, wherein the carrying element is provided with a pivoted journal placed stationary on its underside, oriented downward at an incline, and can pivot around the lengthwise axis of the journal during tipping, and the journal is supported on a tipping element which, for its part, is further mounted on a support element projecting upward from the support part, a support element whose lengthwise axis runs at an angle to the lengthwise axis of the journal and can be pivoted in a controlled way relative to the support element during tipping of the carrying element.
2. Discussion of the Background
To this package conveyor used for sorting packages, accordingly also designated a "sorter" for short, is fed the packages at least at one dispatch point (but frequently also at several dispatch points) so that the packages in each case are placed on the carrying surface, essentially horizontal in the conveying state, of a (tipping-) conveyor element.
If the above discussion or in the following text reference is made to the carrying surface of the conveyor element in the conveying state being "essentially horizontal," this is also to express that the carrying surface can optionally also be made curved, saucer-shaped or angled.
The conveyor line of such a package conveyor can run either only in a horizontal plane or also, at least in sections, inclined to the horizontal or spatially pitched, and in such cases of course care is to be taken that the packages do not unintentionally slide down from the carrying surfaces.
The essential object of such a sorter consists in delivering the packages respectively to one of several delivery stations placed laterally with respect to the conveyor belt, to sort them according to certain criteria. This can be, e.g., postal packages, for example for sorting them according to zip codes or, with a sorter used at an airport, sorting of checked-in baggage according to destination. Here, the packages, before they are dispatched to the sorter, are generally provided with a coding indication or they exhibit from the start an identification or a marking that can be read by a reading device, and the coding indication or marking in the area of the sorter is allocated to a specific delivery station and by a certain device care is taken that a package allocated to a specific delivery station is delivered to the delivery station (laterally) from the sorter and, at the delivery point involved reaches (generally by a chute) a conveyor with a conveying direction running crosswise to the conveying direction of the sorter there, from which it is then further conveyed for further processing.
To achieve the desired delivery of a package to a certain delivery station, it would evidently be basically possible, for one thing, to push a package laterally off the carrying surface (here remaining essentially horizontal) of the conveyor element involved with a ram or the like running essentially crosswise to the conveying direction of the sorter and operated hydraulically or pneumatically. But such a method of operation, especially with the high conveying speeds of sorters achieved today, which can be up to 2 m/sec. and more, is unsatisfactory if only because the package is greatly stressed during such handling. But as careful a handling as possible of the package is desired to a greatest degree practically in all individual cases for sorter applications.
Therefore, conveyor elements for such package conveyors have already been developed in which the carrying surface is to be tipped laterally at a delivery station around an axis of rotation running in the conveying direction and placed symmetrically to the carrying surface, and a central placement of the axis of rotation relative to the carrying surface is selected because generally with such a sorter the delivery stations are placed both to the left and right of the conveyor belt, so that the package (as seen in the conveying direction) accordingly can be delivered as desired to the left or right.
But this already known design has also proven to be unsatisfactory. For one thing, it has turned out that the packages, in numerous applications--especially when they are placed on the carrying surface offset laterally opposite the delivery side--tend to tumble during tipping, which is highly undesirable for a defined and especially careful delivery.
Moreover, during lateral tipping of the carrying surface in the manner described above, an elongated package that is generally placed along its lengthwise direction on a conveying element is delivered by the sorter so that its lengthwise side lies in front, so that the receiving or transfer devices must be made suitably wide or be provided with suitable steering devices, which again does not lead to careful handling of the package and, further, leads to a correspondingly high investment expense.
To improve further the conveyor elements described above, conveyor elements have also become known in which the axis of rotation running in the conveying direction is offset laterally to tip the carrying surface to the lengthwise axis of symmetry of the carrying surface. But generally such an offset cannot be achieved--especially with relatively large carrying surfaces--so that the axis of rotation lies essentially in the area of a lateral lengthwise edge of the carrying element and accordingly the carrying surface, horizontal in the conveying state, is essentially lowered only downwardly during lateral tipping, but only a relatively limited offset of the axis of rotation to the lengthwise axis of symmetry can be achieved, by which the danger of the involved package tumbling (i.e., "wobbling") cannot be sufficiently reduced.
However, since the carrying surface of a conveyor element involved here must be able to be tipped to the left or right as desired at all times for the reasons mentioned above, such a configuration to change from one axis of rotation to the other axis of rotation requires additionally a considerable expense, which entails not only corresponding costs but which, because of the relatively complicated mechanical system, is correspondingly susceptible to trouble. Further, with this known conveyor element, elongated packages are also delivered by the sorter so that their long lengthwise side lies in front, so that in this regard the drawbacks mentioned above are also present and, further, very careful handling of the package cannot be achieved.
From WO 81/01 999 there is known a conveyor element whose carrying surface is simultaneously pivoted to a limited degree during tipping so that an elongated package placed on a carrying element in the lengthwise direction suitably undergoes a certain degree of pivoting. For this purpose, the journal extending downward at an incline from the carrying element is mounted in a stationary bearing whose bearing housing is connected rigidly with the support part of the conveyor element so that during the tipping operation, a certain pivoting of the carrying surface around the stationary lengthwise axis of the journal is possible, and consequently the point of the carrying surface through which the lengthwise axis passes remains stationary.
Although the delivery operation with the conveyor elements known from this patent is improved relative to the prior art described above, a careful handling, especially of elongated packages that lie in the conveying direction on the conveyor elements, is still not nearly optimal, since the pivoting movement given to a package during tipping is very limited and, as in the prior art described above, is produced exclusively by the effect of gravity.
From DE-PS 36 02 861 there has become known a generic conveyor element that is considerably improved relative to the previously known prior art, a conveyor element with which an extremely careful delivery of the packages is guaranteed and, during the delivery operation, a package to be delivered is imparted, beyond the effect of gravity, with a course of movement which is still suitable for a careful delivery and which, relative to the previously known tipping-conveyor element described above, is achieved essentially in that the journal, during tipping of the carrying element, can be pivoted in a controlled way relative to the support element, and further preferably the lengthwise axis of the support element, in the conveying state of the carrying element, runs in mirror symmetry to the lengthwise axis of the journal relative to a horizontal reference plane running between the carrying element on the one hand and the support part on the other hand and the support element, made cone-shaped in the tipping-conveyor element according to DE-PS 36 02 861, is connected rigidly to the support part.
Further, in the tipping-conveyor element known from DE-PS 36 02 861--as in the tipping-conveyor element known from WO 81/01 999--the pivoted journal placed stationary on the underside of the carrying element and oriented downward at an incline is connected with the cone-shaped support element by a universal joint, and the one axis of rotation of the universal joint running at a right angle to the lengthwise axis of the cone-shaped support element runs in the vertical plane in which the lengthwise axes of the journal and the cone-shaped support element run in the conveying state.
The tipping-conveyor element known from DE-PS 36 02 86l, which very decisively differs from the previously known prior art with respect to its structure as well as to its way of functioning, has certainly hardly proven to be in need of improvement in practice with respect to its way of functioning, but from a manufacturing engineering viewpoint, especially with respect to the universal joint placed between the journal on the one hand and the cone-shaped support element on the other hand, it creates very considerable difficulties that are system-inherent and thus cannot to be eliminated. These difficulties lie--completely apart from the very considerable costs of the universal joint, which constitute about 50% of the total costs of the entire tipping-conveyor element--especially in the tolerances to be required (and here not least again the manufacturing costs connected with them). If, namely, the tolerance in the design according to DE-PS 36 02 861 is retained in an extent or range usual for such mechanical devices and in doing so a considerable cost has already been incurred, then these tolerances "accumulate" from the area of the universal joint placed approximately centered in the tipping-conveyor element to the conveyor element or its carrying surface so that the universal joint, when grasped for example with the hands and moved "tipping" around its lengthwise and/or crosswise axis, exhibits a relatively large play which is then itself perceived as unsatisfactory by the users when it is below the threshold or limit beyond which it has a disadvantageous impact on the way the sorter functions. It has turned out that the actual or even only potential customer of such package conveyors (i.e., sorters) are not prepared, or are prepared only with extreme hesitation, to accept a structure with which the conveyor elements, in the unloaded state, can already be moved "tipping" (although of course limited) more or less in all directions by hand. This attitude is probably based on the fear that a package conveyor, whose carrying elements behave suitably already at the start of operation, in a more or less short period, because of the normal, usual wear, changes into a state in which the individual conveyor elements, because of a feared knocking out of their mounting, behave like withered flowers and in each case, in an undesired and unsystematic way, are placed laterally (although only slightly) tipped already during transport. Finally it is feared that this behavior, in the course of a relatively short operating time, could increase so far that it then also acts in a disadvantageous way on the operating behavior and that thus packages slide off the carrying surface laterally already before the set delivery point.
It can be open to question whether or not these fears in fact materialize in the foreseeable operating time, since this prejudice is held (and also completely understandably) by practically all potential users.
This skepticism at least frequently is not unjustified when the carrying surfaces of such a sorter are used for purposes other than those originally intended as a catwalk in the operating pauses. This is the case, e.g., when the operating and maintenance personnel or other third parties climb on the carrying surfaces of the conveyor elements (for example to mount lamps above the conveyor or to change lightbulbs), as is simply not preventable in practice, despite appropriate rules of conduct, especially with respect to non-employees. In such cases, such a tipping-conveyor element that is designed, for example, for a maximum load of maximally 20 or 30 kg, is suddenly loaded with, e.g., 90 kg or more (thus, threefold, fourfold or more) and then, because of these overloads, actually an even larger play can occur in the area of the carrying surface.
Because of the very considerable importance, in this connection it is again pointed out that not least, aspects relating to cost also play a very considerable role here since universal joints, as they are to be used in the tipping-conveyor elements according to WO 81/01 999 or DE-PS 36 02 861, are relatively expensive components which, in the context of the total costs of such a tipping-conveyor element, clearly play a tremendous role with a share of up to 50% and more especially considering that, with a larger sorter, usually at least hundreds of such tipping-conveyor elements are used.